Keep it simple - just call yourselves developers - those techno - titles are things HR gets funded to come up with.

The good thing about no titles is that your role as designer leads to the fun part of the job building and testing and making momma proud your solution works!

Be a team - eliminate artificial barriers - then: give yourself the title that pays the most:0). When you move on - people are not [really] interested in your last title - they're interested in your accomplishments (deliverables)and [your] ability to communicate. They want samples and references more than the lower left corner of a business card.